Apparatus for encapsulating an article within molded polyurethane

ABSTRACT

An apparatus for encapsulating an article within a plastic foam material, such as polyurethane, wherein the article to be packaged is placed within a mold cavity of an adjustable mold, the walls of the mold are adjusted according to the size of the article and a liquid polymeric-isocyanate mix is injected into the mold cavity and allowed to react to form an insoluble, flexible, polyurethane foam which completely encapsulates the article. After the urethane has set, the mold walls are retracted and the encapsulated article is removed. The apparatus consists of a mold form having a baseplate and four upstanding movable sidewalls which define a mold cavity. Each upstanding wall is movable with respect to the other walls thereby to allow for a wide variation in the size of the mold cavity to accommodate wide variations in article size. In addition, a plurality of similar mold forms are provided to rotate on a carousel about a central, liquid polymeric-isocyanate distribution system so that after the liquid has been injected into a mold, the mold may be moved away and the polyurethane allowed to set while liquid is injected into the remaining molds. In this manner, a continuous production line operation may be maintained.

United States Patent Theodorsen 5] Feb. 15, 1972 [72] Inventor: TheodoreE. Theodorsen, Manhasset, NY.

[73] Assignee: Kurt Salmon Associates, Inc., New York,

[22] Filed: Nov. 6, 1969 [21] Appl. No.: 874,563

[52] US. Cl ..425/129, 249/ 162, 425/4,

425/330 [51] Int. Cl ..B29c 3/04 [58] FieldofSearch ..l8/lD,2HA,5E,5BB,5F,

18/5 P, 30 CK, 30 CV, 20 R; 249/91, 161, 162; 279/112, 123; 269/2, 118;264/45, 46

[56] References Cited UNITED STATES PATENTS 785,272 3/1905 Robbins........249/l6l X Dijken et al ..249/91 X Primary ExaminerH. A. Kilby, Jr.Attorney-Curtis, Morris and Safi'ord [57] ABSTRACT An apparatus forencapsulating an article within a plastic foam material, such aspolyurethane, wherein the article to be packaged is placed within a moldcavity of an adjustable mold, the walls of the mold are adjustedaccording to the size of the article and a liquid polymeric-isocyanatemix is injected into the mold cavity and allowed to react to form aninsoluble, flexible, polyurethane foam which completely encapsulates thearticle. After the urethane has set, the mold walls are retracted andthe encapsulated article is removed. The apparatus consists of a moldform having a baseplate and four upstanding movable sidewalls whichdefine a mold cavity. Each upstanding wall is movable with respect tothe other walls thereby to allow for a wide variation in the size of themold cavity to accommodate wide variations in article size. In addition,a plurality of similar mold fomis are provided to rotate on a carouselabout a central, liquid polymeric-isocyanate distribution system so thatafter the liquid has been injected into a mold, the mold may be movedaway and the polyurethane allowed to set while liquid is injected intothe remaining molds. In this manner, a continuous production lineoperation may be maintained.

9 Claims, 4 Drawing Figures APPARATUS FOR ENCAPSULATING AN ARTICLEWITHIN MOLDED POLYURETHANE This invention relates to a method andapparatus for preparing a package comprising an article encapsulated ina shock absorbent exterior casing, such as polyurethane or the like, andmore in particular, to a method and apparatus for molding a polyurethanefoam protective covering and shipping container about an article.

At present, when it is desired to pack an article in a container, forexample for shipping purposes, where the article must be cushioned fromshocks encountered in transit, it is common to pack the article in apaperboard box within a shock absorbent protective material. Polystyreneis most commonly used and the polystyrene is first formed in a mold toobtain a solid slab having a contoured surface which mates with theexterior surfaces of the article; the article is then sandwiched betweentwo or more of the styrene slabs and placed in a paperboard box which isthen sealed. This procedure is inherently expensive and inflexible asseparate molds must be provided for each article to be packaged, thestyrene cushioning pieces must be molded in these molds and the styreneslabs and the article must be manually assembled and inserted in apaperboard box. Additionally, the paperboard boxes are shipped in a flatcondition and must be prepared by opening the boxes, the styrene-encasedarticles placed therein and the boxes sealed.

Additionally, while polystyrene is used because it sets up fast in aheated mold, it is not the best type of plastic material which can beused as a cushioning for shipping articles. A material such aspolyurethane is more desirable because of a greater compressive strengthbut has not been used heretofore because of its relatively longer setuptime in a mold.

It is, therefore, an object of the present invention to provide a methodand apparatus for encapsulating an article within a polyurethane foamcontainer to form a shipping container for the article without requiringthe use of an outer carton.

It is another object of the present invention to provide a method andapparatus for encapsulating an article within a polyurethane foamplastic in a mold which is so constructed as to be adjustable toaccommodate a wide range ofsizes.

It is a further object of the present invention to provide a method andapparatus for encapsulating an article within a foamed polyurethaneplastic material in a rapid and commercially feasible manner so as tolend such a procedure to production line applications.

In a preferred embodiment of the present invention a mold which isadjustable as to size is provided consisting of a baseplate withprovision thereon to elevate an article to be encapsulated above thesurface of the baseplate. Four upstanding walls are provided which inconjunction with the baseplate define a mold cavity and the walls areadjustable on the base plate thereby to vary the size of the moldcavity. In this manner. articles of varying sizes can be accommodated bythe same mold structure. Once an article is placed in its elevatedrelationship with respect to the baseplate of the mold, and each of thewalls of the mold have been adjusted so as to be slightly spaced fromthe article therein, a foamable polyurethane mixture is sprayed into thecavity and allowed to form a polyurethane foam which completelyencapsulates the article therein. Once the foam has set, the walls ofthe mold form are retracted and the encapsulated article is removed fromthe mold and can now be shipped as it is encapsulated in a solidenergy-absorbing polyurethane container.

In the drawings:

FIG. 1 is a perspective view showing a preferred embodi ment oftheadjustable mold;

FIG. 2 is a top plan view showing a plurality of adjustable moldsarranged in a circular carousel with respect to a centralpolyurethane-foaming apparatus;

FIG. 3 is a view, partly in section, taken on line 33 of FIG.

2; and

FIG. 4 is a perspective view similar to FIG. 1 showing an alternativeembodiment for the adjustable mold structure.

With reference now to the drawings and particularly FIG. I,

a mold 10 is provided which defines a mold cavity 12 adaptedto hold anarticle which is to be encapsulated in a cellular plastic material, suchas polyurethane. The mold 10 is provided with a baseplate 14 whichdefines the lower wall of the mold cavity 12 and four upstandingsidewalls l6, 18, 20 and 22 disposed at right angles to each other todefine the mold cavity 12. The upstanding walls 16, 18, 20 and 22 areadjustable along the baseplate 14 to vary the size of the mold cavity12.

A lateral face 24 of wall 16 is parallel to and closely abuts the insideface of wall 22 and, in like manner, the lateral face 26 of wall 18, thelateral face 28 of wall 20 and the lateral face 30 of wall 22 arerespectively parallel to, and closely abut, the inside face of walls 16,18 and 20. Each of the lateral faces 24, 26, 28 and 30 are adapted toslide along the respective inside faces of walls 16, 18, 20 and 22 andalso baseplate 14 to increase or decrease the size of the mold cavity12.

With respect now to FIG. 3 as well, the baseplate l4 ofmold 10 issupported on a support plate 32 by opposed pairs of support members 34and 36, respectively, so that baseplate 14 of mold 10 is slightlyelevated with respect to the support plate 32.

The outside face of each wall 16, 18, 20 and 22 is provided with alongitudinal slot 38 which includes grooved upper and lower extensions40 and 42, respectively, along the length of the slot and opposed pairsof bracket members 44 and 46, respectively, are slidably retained withinslots 38. Each of the brackets in bracket pairs 44 and 46 include aslot-contacting face 48 having extending tab members 50 and 52 which areadapted to fit in, and slide within, groove extensions 40 and 42. Hence,the slot-contacting face 48 of each bracket is positively retainedwithin slot 38 while being adapted for slidable disposition therein.

Each of the brackets in bracket pairs 44 and 46 include an angularlydisposed leg 54 and a vertically disposed leg segment 56. A threadedbore is provided in each vertical leg segment 56 to threadably receive aworm-screw therein. Bracket pair 44 are interconnected to a commonworm-screw 60 and bracket pair 46 are interconnected to a commonworm-screw 62. Each worm-screw 60 and 62 has one portion 64 threadedwith a right-hand thread 66 with the associated bores 56 of brackets 44and 46 being similarly threaded and the other end 68 of each worm-screwthreaded with a left-hand thread 70 to mate with the left-hand thread inthreaded bore 56 of the other of racket pairs 44 and 46. Worm-screw 60is rotatably support d within opposed support members 34, for examplewithin a bore 72 in support column 34, and wormscrew 62 is otatablysupported in opposed support members 36.

s 60 and 62 are disposed to intersect at their approximate midpointsand, as shown in FIG. 3, worm-screw 62 is slightly elevated with respectto worm-screw 60 so that there is a clearance between the twoworm-screws 60 and 62.

An electric motor 74 is operably connected to one end of worm-screw 60and an electric motor 76 is operably con nected to one end of worm-screw62. When activated, motors 74 and 76 cause worm-screws 60 and 62 torotate and, when the worm-screws 60 and 62 are rotated, the opposedpairs of brackets 44 and 46, since they are threadably engaged on eachof the worm-screws 60 and 62, are moved longitudinally along theirrespective worm-screws. Because each worm-screw 60 and 62 and one ofeach bracket pairs 44 and 46 are threaded, respectively, with rightandleft-hand threads, rotation of the worm-screws will cause movement ofbracket pair 44 and bracket pair 46 in opposite directions. Since eachof the brackets 44 and 46 are engaged within the slot 38 on respectivesidewalls 16, 18, 20 and 22, the movement ofthe bracket pairs 44 and 46will also cause movement of respective 0pposed sidewalls 16-20 and18-22. Motors 74 and 76 may operate independently so that only theopposed pairs of sideplates l6 and 20 or 18 and 22 may be moved.

Each of the sideplates 16, 18, 20 and 22 have a longitudinally extendingslot 78 on their top wall 80. A U-shaped member 82 has one leg 84secured in the top wall 80 in each sideplate 16, 18, 20 and 22 adjacentthe respective abutting lateral face 24, 26. 28 and 30 so that the otherleg member 86 of member 82 is slidably disposed within the slot 78 ofthe contiguous sideplate. Hence, as one sideplate moves relative to itsrespective adjacent sideplate, the leg 86 of U-shaped member 82 slidesalong slot 78 and maintains a contacting relationship between any twoperpendicularly disposed sideplates. In this manner, when the opposedpairs of sideplates l8 and 22 move, for example away from each other,contact between sideplates l8 and 20 is maintained by U- shaped member82 and side plate 20 is accordingly moved in the same direction as sideplate 18. Concurrently, the U- shaped member 82 interconnectingsideplates l6 and 22 causes sideplate 16 to be moved in the samedirection of movement as sideplate 22. Thus, intimate contact betweenall of the sideplates is maintained when any two of them are moved.Similarly, if sideplates 16 and 20 are moved, sideplates l8 and 22 wouldalso be moved accordingly as a result of the contact maintained by theU-shaped members 82.

While the surfaces of contact between each of the sideplates may bemachined to a relatively high finish, so as to reduce friction betweenthe mating surfaces as one side plate is moved relative to the other, aslight gap will exist between the mating surfaces which would allow theseepage of the liquid polymeric-isocyanate mix when this mix is injectedinto the mold. Accordingly, once the desired mold size is obtained, theslight gap between the abutting lateral faces 24, 26, 28 and 30 and itscontiguous sideplate is reduced by actuation of electromagnets 88 and 90secured to the outside face of each of sideplates l6, I8, 20 and 22.Electromagnets 88 and 90 are suitably connected to a source ofelectrical energy (not shown) in any conventional manner. Thus, when theelectromagnets are energized, they tend to draw the contiguoussideplates together, It is to be understood that while electromagnetshave been specifically disclosed as a means to close the gap formed byabutting sideplates, any other suitable means can be used. As an exampleof alternative constructions which may be employed, pneumatic cylindersmay be provided which are pivotally secured to the outside face of walls16, 18,20 and 22 having the piston extension secured near the free endof an abutting sidewall. When it is desired to close the gap the pistoncan be made to retract thus drawing the abutting sidewalls together.Additionally, tension springs could be provided which could be manuallyinstalled once the desired mold size has been achieved.

As seen in FIG. 3, an article 92 to be encapsulated in the mold issupported above the baseplate 14 on a plurality of pins 94 to allow theliquid mix injected into the mold to flow under the article. The pins 94are preferably conically shaped or frustoconically shaped within moldcavity 12 so that after the polyurethane has foamed and set and thesidewalls of the mold retracted to free the now encapsulated article,the polyurethane-encapsulated article may be lifted free of the pinswith little resistance. Preferably, four pins are used spaced about theapproximate center portion of the mold cavity 12.

Reference is now made to FIG. 2 where there is shown a preferredarrangement for a plurality of molds 10 rotatably disposed about acentralv polymeric-isocyanate mix dispensing apparatus 96. This may beany commercially available polyurethane froth foam machine such as theModel l90ll froth foam machine manufactured by Pyles Industries.Apparatus 96 has radiating therefrom a flexible liquid-dispensing arm 98through which the liquid polymeric-isocyanate mix is fed to the exitnozzle 100 (see FIG. 3 as well) and allowed to flow into the mold cavity12. Arm 98, besides being flexible to allow vertical movement of thedispensing arm, is also pivotally secured to the apparatus 96 as at 102to allow for proper positioning of the nozzle 100 over a mold 10.

With reference to FIG. 3, it is seen that the support plate 32 isprovided with brackets 104 on its underside which carry rotatablymounted wheels 106 therein adapted to ride along circularly disposedtracks I08 supported on a bed 110 secured to vertical legs 112. As shownin FIG. 2, six separate mold units 10 are provided, although any numbermay be employed, with all the mold units being rotatably disposed sothat they rotate freely on tracks 108 about the liquid'distributionapparatus 96. Preferably, each of the support units 32 are secured as at1 14 so that the total array of mold units 10 rotate in unison aboutdistribution apparatus 96, In this manner, a continuous production lineset up may be obtained. After an article has been placed in a mold l0,and the walls adjusted, in a manner to be explained more fullyhereinbelow, and the liquid polymeric-isocyanate mix injected into themold. the mold is rotated away and allowed to foam and set. B the timethis particular mold has moved back to the injecting station. theencapsulated article is ready to be removed and the procedure repeated.

The inside surfaces ofthe mold cavity 12 preferably are provided with aTeflon lining or a spray-coating of a release agent to which thepolyurethane foam will not adhere after it has set. In operation, thearticle to be encapsulated, also coated with a release agent, ifnecessary, or enclosed in a plastic bag of polyethylene or the like, towhich the polyurethane foam will not adhere, is placed in the open moldso that it rests above the baseplate on the mold cavity on locating pins94. In the alternative, the article 92 to be encapsulated may be placedon a slab of preformed polyurethane foam which is inserted into the moldcavity 12 and the article 92 placed thereon. At this point, motors 74and 76 are actuated to rotate worm-screws 60 and 62 so that the opposedbracket pairs 44 and 46 are moved toward each other, thus causing thesidewalls 16, 18, 20 and 22 to close inwardly upon the article 92 withinmold cavity 12. Motors 74 and 76 are low power DC motors which areadapted to shut off when walls 16, 18, 20 and 22 contact and applyslight pressure against the article 92 within the mold cavity 12. Atthis point, the sidewalls of the mold 10 are in direct contact with thearticle 92 therein and motors 74 and 76 automatically reverse themselvescausing opposed pairs of brackets 44 and 46 to move away from each otherthus bringing the sidewalls of the mold outwardly away from the article92. Preferably, the reversal of motors 74 and 76 is only for apredetermined period of time sufficient to withdraw the side walls 16,18, 20 and 22 of mold 10 a predetermined distance away from the article92 so that a predetermined thickness for the encapsulating polyurethanefoam may be molded about the article 92.

Once the size of mold cavity 12 has been achieved for a particulararticle 92 therein, the mold 10 is rotated on tracks 108 to the vicinityof the liquid polyurethane discharge nozzle in readiness to receive apredetermined quantity of the liquid polymeric-isocyanate mix which issprayed into the mold cavity 12.

Since the liquid mix, when it begins to foam, increases in volume on theorder of 30 to l, the amount of liquid mix sprayed into mold 12 must becarefully controlled to insure that after the polyurethane foams, itwill not overflow the mold cavity. Accordingly, means are provided toafford a volumetric calculation in order to determine the quantity ofpolymeric-isocyanate mix or shot-charge which must be injected into themold to sufficiently encapsulate the article 92 once the polyurethanehas foamed and set. As an example of the type of apparatus which may beused to make a volumetric calculation, the distance one of the brackets44 and one of the brackets 46 travels when the mold size is adjusted canbe readily determined and correlated to a particular area enclosed bythe four sidewalls 16, 18, 20 and 22. A linear rheostat 116 mounted onsupport plate 32 is positioned beneath the path of travel of thevertical leg segment 56 of bracket 44 and 46 and leg segment 56 carriesan electrical contact member 117 which rides along rheostat 116. Therheostat I16 and contact member 117 are operably connected in anelectrical circuit (not shown) and the voltage change across rheostat116 as brackets 44 and 46 move from the inwardmost position, i.e., wheresidewalls l6, 18, 20 and 22 are in contact with article 92, to theoutermost position provides an indication of the area of the enclosedmold less the area occupied by article 92. In this manner, the relativeposition of the brackets can be correlated automatically to a particularenclosed area for the mold cavity 12.

In addition, a vertical height measurement is made which, whencorrelated to the area measurement made by rheostat 116, providesvolumetric indication. For this purpose, a boom 118 is provided which ispivotally mounted at 120 to an upstanding support 122 secured to supportplate 110 at one station 123, for example where the mix is injected intothe mold. One end of boom 118 includes a leg 124 adapted to contact theupper surface of article 92 within mold l0 and the other end of boom 118is provided with an electrical contact member 126 adapted to slidablycontact an arcuate rheostat 128. The portion of boom 118 between pivot120 and rheostat 128 is counterbalanced by a weight 130 so that the boomis maintained in equilibrium. Rheostat 128 is held in an L- shapedbracket support 132 which is fixed to support 122. As with the rheostats116, rheostat 128 and contact member 126 are operably connected in anelectrical circuit (not shown). Support 122 is pivotally mounted onsupport plate 110 in any conventional manner, for example shaft 122 maybe rotatably supported within a bearing housing 134 on support plate110, so that boom 118 can be rotated to a position over mold and thenrotated away after an appropriate height measurement has been made.

Once an article 92 is placed within mold cavity 12 and the sidewalls l6,18, and 22 have been adjusted to the proper position, boom 118 isrotated to a position over article 92. The operator then pivots boom 118about pivot 120 until leg 124 contacts the top of article 92. Thispivoting movement will result in movement of contact member 126 alongrheostat 128 resulting in an appropriate voltage change in theelectrical circuit in which the rheostat 128 and contact member 126 areconnected.

The changes in the three voltages across rheostats 116 and rheostat 128are sent to an electrical control circuit where the changes in voltageare correlated to a particular volume of molded polyurethane necessaryto completely encapsulate article 92. This information is then in turnfed to a control device on the dispensing apparatus 96 which thenautomatically sets the quantity ofliquid polymeric-isocyanate mix to beinjected for a particular molding operation. Thus, as soon as theoperator actuates the apparatus 96, the controls would be automaticallyset to inject the proper amount of liquid mix so that when thepolyurethane has foamed and set, the article 92 would be completelyencapsulated. In the alternative, the quantity of liquid to be injectedinto the mold may be manually set according to the indicated volumeneeded.

With reference now to FIG. 4, there is shown an alternate embodiment fora mold 10'. The mold 10 may be adjusted to achieve a mold cavity 12 ofvaryingsize although not in the finite range of size achieved by themold 10 shown in FIG. 1. In this embodiment, the baseplate 214 and twovertical walls 216, and 218 are integrally formed to achieve unitaryconstruction. A third upstanding wall 222 is provided at right angles towall 216 and slidable therealong so that its relative position withrespect to wall 218 may be adjusted. The fourth wall 222 of mold 10 isadded to complete the mold cavity 12 and includes a clip bracket 224which overlies wall 218 and holds the wall 222 firmly thereagainst. Aplurality of walls 222 are provided with varying lengths and theadjustment of the mold cavity is made by selecting an appropriate lengthwall 222, moving wall 220 away from wall 218, inserting the selectedlength wall 222 and then moving wall 220 firmly against free edge 228 ofwall 222 to complete the mold cavity 12'. Wall 220 may be manuallyshifted along baseplate 214 to the desired position but, preferably, ismechanically shifted, i.e., by a motor and worm-screw arrangement, asshown in FIG. 3, or by a manual crank 230 having a worm-screw extension232 which is threadably received within a threaded bore 234 ofa bracket236. Bracket 236 includes an extension plate 238 which is fastened, asby welding, to the exterior face of movable wall 220. In addition,support brackets 240 are provided on opposite sides of the centraladjusting bracket 238 which are also fixed to the exterior surface ofmovable wall 220. Brackets 240 include an Lshaped leg extension 242having one leg 250 adapted to slide within a guide track 252 on theunderside of baseplate 214. In this manner, discrete adjustments to themold cavity size may be made by selecting a suitably dimensioned wall222 and adjusting the position of movable wall 220 so as to closely abutthe selected wall 222.

What is claimed is:

1. Apparatus for encapsulating an article within an energyabsorbingsolid material comprising:

an adjustable mold form,

said mold form including a baseplate defining a bottom of said mold formand at least four upstanding wall members which together with saidbaseplate define an enclosed mold cavity,

each said wall being movable with respect to the other three walls andsaid baseplate thereby to provide a finite variation in the size of themold cavity,

each said upstanding wall being disposed perpendicular to an adjacentwall with one vertical edge being in sliding contact with the insideface of the next adjacent wall and the opposed vertical edge being freestanding and not in contact with another upstanding wall whereby eachsaid wall is adapted for sliding movement in a path parallel to theinside face of the adjacent wall in sliding contact with the verticaledge and in a path perpendicular to said adjacent wall,

means operably connected to each said upstanding wall to selectivelymove each said wall member toward and away from an opposed wall member,and

means to dispense a liquid foamable plastic mixture into said moldcavity thereby to encapsulate an article therein when said foamableplastic mixture has foamed and set.

2. Apparatus as defined in claim 1 wherein said means to dispense afoamable liquid plastic mixture comprises a liquid polymeric-isocyanatemix-dispensing apparatus to dispense a liquid mixture which upon foamingand setting forms a solid, energy-absorbing polyurethane plastic, andmeans associated with said baseplate to elevate an article placed withinsaid mold cavity above said baseplate thereby to allow said foamableliquid plastic mixture to flow under said article to completelyencapsulate said article when said mixture has foamed and set.

3. Apparatus as defined in claim 2 wherein a plurality of mold forms areprovided, each one of said plurality of mold forms being mounted on amovable carriage, each said carriage being adapted to be moved to thevicinity of the discharge nozzle of said liquid mixture-dispensingapparatus to receive a charge of said mix and to be moved away from saidapparatus while said mix foams and sets thereby to provide a continuousproduction line operation.

4. Apparatus as defined in claim 1 wherein opposed pairs of saidupstanding walls are operably interconnected so that said opposed pairsof upstanding walls move in opposite directions when moved to vary thesize of said mold cavity.

5. Apparatus as defined in claim 4 wherein said means operablyinterconnecting opposed pairs of said upstanding walls includes bracketmembers retained by and slidably disposed within a horizontal slot onthe outside face of each said upstanding wall, said bracket membersincluding a leg member extending below said base plate, a threaded borein each said leg member below the plane of the bottom surface of saidbase plate, and a threaded worm-screw operably engaged within thethreaded bores ofopposed bracket members.

6. Apparatus as defined in claim 5 wherein one of said opposed pairs ofinterconnected bracket members and the seg ment of the worm-screwengaged therewith are threaded with a right-hand thread and the other ofsaid opposed pairs of interconnected bracket members and the segment ofthe wormscrew engaged therewith are threaded with a left-hand thread,and a motor operably connected to one end of each of said nun-n n--worm-screws to selectively drive each said worm-screws in two directionswhereby when said worm-screws are driven in one direction the opposedpairs of upstanding walls operably connected to said worm-screws arecaused to move toward each other and when driven in the oppositedirection are caused-to move away from each other.

7. Apparatus for encapsulating an article within an energyabsorbingsolid polyurethane envelope comprising:

an adjustable mold form comprising a bascplate and four upstandingsidewalls defining a mold cavity therein,

said upstanding walls being slidably disposed with respect to each otherand said baseplate thereby to vary the internal dimensions of said moldcavity,

means to dispense a foamable liquid polymeric-isocyanate mixture whichupon foaming and setting forms a solid, energy-absorbing polyurethaneplastic, and

means to determine the volume of the internal mold cavity after the moldis adjusted for a particular article to be encapsulated and to determinethe quantity of liquid polymeric-isocyanate mix to be injected into saidmold cavity to completely encapsulate said article.

8. Apparatus as defined in claim 7 wherein each said upstanding wall hasassociated therewith a bracket member slidably retained in a horizontalslot on the outside face of said wall, said bracket including a legsegment extending below said baseplate and having a threaded boretherein, opposed pairs of said brackets being interconnected on a commonworm'screw threadably engaged in said bores with one end of saidworm-screw being threaded with a right-hand thread and the other endwith a left-hand thread whereby when said worm-screw is rotated in onedirection the brackets and upstanding walls associated therewith movetoward each other and when rotated in the opposite direction thebrackets and upstanding walls associated therewith move away from eachother, and drive means operably connected to one end ofeach worm-screwoperative to selectively drive said worm-screw in opposite directions ofrotation.

9. Apparatus as defined in claim 8 wherein said means to determine thequantity of liquid polymeric-isocyanate mix comprises a rheostatpositioned adjacent one end of each said worm-screw, an electricalcontact member adapted to slide along each said rheostat and carriedvbyone of said bracket members on each said worm-screw whereby when saidupstanding walls are moved from a first position in contact with saidarticle within said mold cavity to a second position a predetermineddistance away from said article, the movement of said electricalcontacts along each said rheostat is adapted to produce a change involtage impressed thereacross which is correlated to an area of theenclosed mold cavity less the area occupied by said article, and a boompivotally mounted intermediate its length above the top of said moldform having one end adapted to pivot into contact with the top of saidarticle and an electrical contact member on its other end, a rheostathaving an arcuate shape supported on a support member on which said boompivots positioned to contact said electrical contact member whereby whensaid boom is pivoted to a position in contact with said article saidelectrical contact member in contact with said arcuate rheostat producesa change in the voltage impressed thereacross which together with thearea determined by said first-named rheostats produces a volumetricindication of the enclosed mold cavity.

2. Apparatus as defined in claim 1 wherein said means to dispense afoamable liquid plastic mixture comprises a liquid polymeric-isocyanatemix-dispensing apparatus to dispense a liquid mixture which upon foamingand setting forms a solid, energy-absorbing polyurethane plastic, andmeans associated with said baseplate to elevate an article placed withinsaid mold cavity above said baseplate thereby to allow said foamableliquid plastic mixture to flow under said article to completelyencapsulate said article when said mixture has foamed and set. 3.Apparatus as defined in claim 2 wherein a plurality of mold forms areprovided, each one of said plurality of mold forms being mounted on amovable carriage, each said carriage being adapted to be moved to thevicinity of the discharge nozzle of said liquid mixture-dispensingapparatus to receive a charge of said mix and to be moved away from saidapparatus while said mix foams and sets thereby to provide a continuousproduction line operation.
 4. Apparatus as defined in claim 1 whereinopposed pairs of said upstanding walls are operably interconnected sothat said opposed pairs of upstanding walls move in opposite directionswhen moved to vary the size of said mold cavity.
 5. Apparatus as definedin claim 4 wherein said means operably interconnecting opposed pairs ofsaid upstanding walls includes bracket members retained by and slidablydisposed within a horizontal slot on the outside face of each saidupstanding wall, said bracket members including a leg member extendingbelow said base plate, a threaded bore in each said leg member below theplane of the bottom surface of said base plate, and a threadedworm-screw operably engaged within the threaded bores of opposed bracketmembers.
 6. Apparatus as defined in claim 5 wherein one of said opposedpairs of interconnected bracket members and the segment of theworm-screw engaged therewith are threaded with a right-hand thread andthe other of said opposed pairs of interconnected bracket members andthe segment of the worm-screw engaged therewith are threaded with aleft-hand thread, and a motor operably connected to one end of each ofsaid worm-screws to selectively drive each said worm-screws in twodirections whereby when said worm-screws are driven in one direction theopposed pairs of upstanding walls operably connected to said worm-screwsare caused to move toward each other and when driven in the oppositedirection are caused to move away from each other.
 7. Apparatus forencapsulating an article within an energy-absorbing solid polyurethaneenvelope comprising: an adjustable mold form comprising a baseplate andfour upstanding sidewalls defining a mold cavity therein, saidupstanding walls being slidably disposed with respect to each other andsaid baseplate thereby to vary the internal dimensions of said moldcavity, means to dispense a foamable liquid polymeric-isocyanate mixturewhich upon Foaming and setting forms a solid, energy-absorbingpolyurethane plastic, and means to determine the volume of the internalmold cavity after the mold is adjusted for a particular article to beencapsulated and to determine the quantity of liquidpolymeric-isocyanate mix to be injected into said mold cavity tocompletely encapsulate said article.
 8. Apparatus as defined in claim 7wherein each said upstanding wall has associated therewith a bracketmember slidably retained in a horizontal slot on the outside face ofsaid wall, said bracket including a leg segment extending below saidbaseplate and having a threaded bore therein, opposed pairs of saidbrackets being interconnected on a common worm-screw threadably engagedin said bores with one end of said worm-screw being threaded with aright-hand thread and the other end with a left-hand thread whereby whensaid worm-screw is rotated in one direction the brackets and upstandingwalls associated therewith move toward each other and when rotated inthe opposite direction the brackets and upstanding walls associatedtherewith move away from each other, and drive means operably connectedto one end of each worm-screw operative to selectively drive saidworm-screw in opposite directions of rotation.
 9. Apparatus as definedin claim 8 wherein said means to determine the quantity of liquidpolymeric-isocyanate mix comprises a rheostat positioned adjacent oneend of each said worm-screw, an electrical contact member adapted toslide along each said rheostat and carried by one of said bracketmembers on each said worm-screw whereby when said upstanding walls aremoved from a first position in contact with said article within saidmold cavity to a second position a predetermined distance away from saidarticle, the movement of said electrical contacts along each saidrheostat is adapted to produce a change in voltage impressed thereacrosswhich is correlated to an area of the enclosed mold cavity less the areaoccupied by said article, and a boom pivotally mounted intermediate itslength above the top of said mold form having one end adapted to pivotinto contact with the top of said article and an electrical contactmember on its other end, a rheostat having an arcuate shape supported ona support member on which said boom pivots positioned to contact saidelectrical contact member whereby when said boom is pivoted to aposition in contact with said article said electrical contact member incontact with said arcuate rheostat produces a change in the voltageimpressed thereacross which together with the area determined by saidfirst-named rheostats produces a volumetric indication of the enclosedmold cavity.